LCM and HCF

The HCF of 24a²b and 32ab² is

HCF (28, 35)

(a)  

What is the Highest Common Factor (HCF) of the number pair 4 and 6?

• 1

• 2

• 3

• 4

Is this question asking to find GCF or LCM?

• GCF

• LCM

Two neon signs are turned on at the same time.  Both signs blink as they are turned on.  One sign blinks every 9 seconds.  The other sign blinks every 15 seconds.  In how many seconds will they blink together?

• 30

• 45

• 50

• 90

Sophie checks her bike for repairs every 9 days and Susan check hers every 12 days. If they both check their bikes today, after how many days do they next both check their bike again?

• HCF

• LCM

Tom and Claire both like do short exercise that involve small breaks. Tom does a short burst of exercise every 2 minutes, and Claire does hers every 3 minutes. If they start doing their exercise at 9:00am, when do they both do their exercises again?

• HCF

• LCM

Find the HCF of 12 and 16...

• 2

• 4

• 6

• 8

Find the LCM of 12 and 16...

• 48

• 36

• 64

• 96

Find the HCF of 8 and 24 ...

• 2

• 4

• 6

• 8